Question

With Ranges in Ruby you can do 0..5 to include all numbers between and including 0 and 5. You can also do 0...5 to include the same numbers except 5 is not included.

(1..5) === 5
=> true
(1...5) === 5
=> false
(1...5) === 4.999999
=> true

是否有办法排除第一个数字,而不是最后的数字来取得这样的结果?

(1...5) === 1
=> false
(1...5) === 1.00000001
=> true

Answer 1

没有,这种范围没有内在支持。您不妨推出自己的<代码>。如果有必要采取这种行动,那么类同。

Answer 2

Not natively with a Range. You can mess with its mind but you re better off using an incremented first value. This is ugly but:

[(1..5).to_s].map{ |s| a,b=s.split( .. ).map{|i| i.to_i}; (1+a .. b) } #=> [2..5]

或

Range.new(*[(1..5).to_s].map{ |s| a,b=s.split( .. ).map{|i| i.to_i}; [1+a,b] }.flatten) #=> 2..5

或

irb(main):004:0> asdf = (1..5)
=> 1..5
irb(main):005:0> Range.new(asdf.min.succ, asdf.max)
=> 2..5

无代表认为是过分的。

Answer 3

除只发送<条码>,第1条_arg.succ,而不是<条码>,第1条_arg? 无,对此没有特别支持。

Answer 4

您可以mon骑马,添加一种方法,以掌握你想要的方式。注

class Range
    def exclusive()
        Range.new(self.first+1, self.last-1)
    end
end

(1..5).exclusive === 5
==>false
(1..5) === 5
==>true

了解骑马托车,因为它改变了现有班级的功能。在本案中,这样做可能更好,但鉴于这个问题,这是一个可以接受的答案。

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